Trotting Control of Load-Carrying Quadruped Walking Vehicle with Load Variations Based on the Centroidal Dynamics and Adaptive Sliding Mode Control

Yongying Tan,Huaying Li,Shousong Han,Zhiqiang Chao,Xiangbo Liu

doi:10.1155/2020/7154254

Abstract

Aiming at the control problems for load variations of the load-carrying quadruped walking vehicle, the method combining centroidal dynamics and adaptive sliding mode control is proposed to ensure the weight adaptation and improve the tracking accuracy of forward speed and lateral speed. The motion control of the walking vehicle is divided into two parts: torso motion control and swinging legs motion control. The control methods of centroidal dynamics and task space PD are applied to the motion control of the torso, and the virtual model control method is applied to the motion control of swinging legs. Then, the adaptive sliding mode control algorithm is applied in the height direction of the vehicle to realize the adaptation to weight change and the weight identification, and the tracking accuracy of forward speed and lateral speed is improved by combining the centroidal dynamics. Adams and Simulink are used to simulate the trotting gait on the flat ground and slope when the weight of walking vehicle changes, and comparisons are made with the virtual model control method. The results show that the method combining centroidal dynamics and adaptive sliding mode control can realize the adaptability to load variations and reduce the forward speed and lateral speed tracking error, which proves the effectiveness of the proposed control method.

Highlights

Legged locomotion enables humans and quadruped animals to walk on rough terrains with a certain amount of loads
According to the joint-space dynamic equations (6), the vehicle height direction is most sensitive to load variations. erefore, the adaptive sliding mode controller is applied to the height control and the weight identification of the walking vehicle, and the identified weight is put into the centroidal dynamics equation
In order to analyze the influence of parameters of adaptive sliding mode control and verify the effectiveness of the control algorithm, Simulink and Adams are used for the trotting gait simulations of the load-carrying quadruped walking vehicle

Summary

Introduction

Legged locomotion enables humans and quadruped animals to walk on rough terrains with a certain amount of loads. To adapt to the load variations of biped walking vehicles, Chew et al [15, 16] applied the adaptive sliding mode control method to the height control of the vehicle. E methods proposed by Chew and Hu have great reference value They did not consider the problems of speed tracking when the weight changes and the characteristics of the dynamic system are not fully utilized. Heijmink et al applied the PI2 learning method to the control parameters adjustments of quadruped walking vehicles [21]. Focchi et al [23] applied the centroidal dynamics control method to the static gait control of quadruped walking vehicles. Based on the kinematics and centroidal dynamics modeling of the walking vehicle, we combine centroidal dynamics with adaptive sliding mode control to achieve the expected height and speed tracking during the load variations. Torso mass (without load) Distance between the origins of forward and rear leg-based coordinate frames Distance between origins of leftward and rightward leg-based coordinate frames Vertical distance between the barycentric coordinate frame and leg-based coordinate frame

J11 6 11 J12

Control Method of the Load-Carrying Quadruped Walking Vehicle

Trotting Gait Simulations of the LoadCarrying Quadruped Walking Vehicle

Findings

Conclusions